Myofibrillar alkaline protease activity in rat heart and its responses to some interventions that alter cardiac size

W. Sue, T. Griffin, Kern Wildenthal

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

The myofibrillar fraction of rat heart homogenates possesses proteolytic activity with an alkaline pH optimum, similar to that reported in skeletal muscle. The specific activity of this "myofibrillar alkaline protease" ("MAP") increases progressively with age. Prolonged starvation and streptozotocin-induced diabetes mellitus, with their attendant cardiac atrophy, cause 25 to 30% increases in the specific activity of MAP. Thyroxine-induced cardiac hypertrophy is accompanied by a 20 to 45% decrease in MAP, which returns to normal during regression of hypertrophy after cessation of thyroid treatment. Isoproterenol-induced cardiomyopathy is accompanied by a progressive reduction in MAP to 80% of control during the first day after injection with a sustained reduction over the next week. These results indicate that a non-lysosomal proteolytic enzyme (or enzymes) is associated with the myofibrillar fraction of rat hearts; this enzyme system possesses maximum activity at an alkaline pH and may undergo significant changes during cardiac hypertrophy, atrophy, or injury.

Original languageEnglish (US)
Pages (from-to)669-676
Number of pages8
JournalJournal of Molecular and Cellular Cardiology
Volume10
Issue number7
DOIs
StatePublished - Jul 1978

Keywords

  • Aging
  • Cardiac atrophy
  • Cardiac hypertrophy
  • Cathepsin D
  • Development
  • Diabetes mellitus
  • Isoproterenol
  • Proteolytic enzymes
  • Starvation
  • Thyrotoxicosis

ASJC Scopus subject areas

  • Molecular Biology
  • Cardiology and Cardiovascular Medicine

Fingerprint Dive into the research topics of 'Myofibrillar alkaline protease activity in rat heart and its responses to some interventions that alter cardiac size'. Together they form a unique fingerprint.

  • Cite this